/// <summary>
/// Starts playing the open media URI.
/// </summary>
public void Play()
{
PlayCommand command = null;
lock (SyncLock)
{
command = Commands.FirstOrDefault(c => c.CommandType == MediaCommandType.Play) as PlayCommand;
if (command == null)
{
command = new PlayCommand(this);
EnqueueCommand(command);
}
}
WaitFor(command);
}
/// <summary>
/// Performs the actions that this command implements.
/// </summary>
internal override void ExecuteInternal()
{
var m = Manager.MediaElement;
WasPlaying = m.IsPlaying;
var pause = new PauseCommand(Manager);
pause.ExecuteInternal();
var initialPosition = m.Clock.Position;
m.SeekingDone?.Reset();
var startTime = DateTime.UtcNow;
try
{
var main = m.Container.Components.Main.MediaType;
var t = MediaType.None;
// 1. Check if we already have the block. If we do, simply set the clock position to the target position
// we don't need anything else.
if (m.Blocks[main].IsInRange(TargetPosition))
{
m.Clock.Position = TargetPosition;
return;
}
// Signal to wait one more frame dcoding cycle before
// sending blocks to the renderer.
m.HasDecoderSeeked = true;
// wait for the current reading and decoding cycles
// to finish. We don't want to interfere with reading in progress
// or decoding in progress
m.PacketReadingCycle?.WaitOne();
// Capture seek target adjustment
var adjustedSeekTarget = TargetPosition;
if (main == MediaType.Video && m.Blocks[main].IsMonotonic)
{
var targetSkewTicks = (long)Math.Round(
m.Blocks[main][0].Duration.Ticks * (m.Blocks[main].Capacity / 2d), 2);
adjustedSeekTarget = TimeSpan.FromTicks(adjustedSeekTarget.Ticks - targetSkewTicks);
}
// Clear Blocks and frames, reset the render times
foreach (var mt in m.Container.Components.MediaTypes)
{
m.Blocks[mt].Clear();
m.LastRenderTime[mt] = TimeSpan.MinValue;
}
// Populate frame queues with after-seek operation
var frames = m.Container.Seek(adjustedSeekTarget);
m.HasMediaEnded = false;
// Clear all the blocks. We don't need them
foreach (var kvp in m.Blocks)
{
kvp.Value.Clear();
}
// Create the blocks from the obtained seek frames
foreach (var frame in frames)
{
m.Blocks[frame.MediaType]?.Add(frame, m.Container);
}
// Now read blocks until we have reached at least the Target Position
while (m.Container.IsAtEndOfStream == false &&
m.Blocks[main].IsFull == false &&
m.Blocks[main].IsInRange(TargetPosition) == false)
{
// Read the next packet
t = m.Container.Read();
// Ignore if we don't have an acceptable packet
if (m.Blocks.ContainsKey(t) == false)
{
continue;
}
// move on if we have plenty
if (m.Blocks[t].IsFull)
{
continue;
}
// Decode and add the frames to the corresponding output
frames.Clear();
frames.AddRange(m.Container.Components[t].ReceiveFrames());
foreach (var frame in frames)
{
m.Blocks[t].Add(frame, m.Container);
}
}
// Handle out-of sync scenarios
if (m.Blocks[main].IsInRange(TargetPosition) == false)
{
var minStartTime = m.Blocks[main].RangeStartTime.Ticks;
var maxStartTime = m.Blocks[main].RangeEndTime.Ticks;
m.Logger.Log(MediaLogMessageType.Warning,
$"SEEK TP: Target Pos {TargetPosition.Format()} not between {m.Blocks[main].RangeStartTime.TotalSeconds:0.000} and {m.Blocks[main].RangeEndTime.TotalSeconds:0.000}");
if (adjustedSeekTarget.Ticks < minStartTime)
{
m.Clock.Position = TimeSpan.FromTicks(minStartTime);
}
else if (adjustedSeekTarget.Ticks > maxStartTime)
{
m.Clock.Position = TimeSpan.FromTicks(maxStartTime);
}
else
{
m.Clock.Position = TargetPosition;
}
}
else
{
// TODO: handle this case correctly. The way this is handled currently sucks.
if (m.Blocks[main].Count == 0 && TargetPosition != TimeSpan.Zero)
{
m.Clock.Position = initialPosition;
}
else
{
m.Clock.Position = TargetPosition;
}
}
}
catch (Exception ex)
{
// Log the exception
m.Logger.Log(MediaLogMessageType.Error,
$"SEEK E: {ex.GetType()} - {ex.Message}. Stack Trace:\r\n{ex.StackTrace}");
}
finally
{
if (m.HasDecoderSeeked)
{
m.Logger.Log(MediaLogMessageType.Debug,
$"SEEK D: Elapsed: {startTime.FormatElapsed()} | Target: {TargetPosition.Format()}");
}
m.SeekingDone?.Set();
if (WasPlaying)
{
var play = new PlayCommand(this.Manager);
play.ExecuteInternal();
}
}
}